Electric selective remote control system



Jan, 3, 1933. B. H. LEESON ET AL 1,893,479

ELECTRIC SELECTIVE REMOTE CONTROL SYSTEM Filed March 25, 1950 2 Sheets-Sheet l 1933. B. H. LEEsoN ET AL 5 3 ELECTRIC SELECTIVE REMOTE CONTROL SYSTEM Filed March 25, 1930 2 Sheets-Sheet 2 Patented Jan. 3, 1933 UNETED STATES PATENT ()FFKIE BRUCE HAMER LEESON, OF TYNEMOUTH, AND DOUGLAS EDWARD LAMBERT, OF HAIR- PENDEN, ENGLAND, ASSIGNORS TO A. REYELOLLE & GOMEANY LEMITED, OF HEB- BUR-N-ON-TYNE, ENG-LAND, A CGB'IIPANY O1 GREi'eT Bl ti'lzhl ELECTRIC SELECTL J'E vREIS.-ZEOIE CONTROL SYSTEM Application filed March 25, 1930, Serial No.

This invention relates to electric selective remote control systems for a number of circuit-breakers or other apparatus at an electric power substa ion of the kind in which mefhanisms are provided at the substation and the control station and are connected tonether by pilot wires, whereby an operator at the control station can transmit selecting current to the substation to cause the selec tion of the individual circuit-breakers or other apparatus, wnilst supervisory indicating ci'irrents can be transmitted from the substation to the control station for the purpose of giving an indication of the condition of the selected apparatus, with or without means for transmittii'ig other currents such for example as executive currents for causing the operation or selected substation apparatus, or alarm currents for giving an alarm at the con trol station in the event of a change occurring automatically in the condition of the substation controlled apparatus, or metering currents for giving meter readings at the control station of the condition of circuits or apparatus at the substation. The term remote control currents will hereinafter be employed to designate. generally all such currents whether for selecting or indicating or executive or other purposes.

The primary object of the present invention is so to arrange such a remote control *ystem as to enable some of the pilot wires normally employed for carrying remote control currents to be temporarily borrowed without harmful interferences with the syscm for other purposes, such for example as the transmission of currents in a protective system for a feeder or like circuit.

The electric selective remote control system according to the present invention employs four pilot wires to carry the remote control arre' ts, and is so arranged that the remote control currei is passing over either of two of the pilot wires are such that the temporary disconnection of the two pilot wires will not cause im-orrcct operation of the remote control apparatus. The system is also so arranged that, whenever these two pilot wires are connected together through remote control apparatus at either end, such apparatus 438,890, and in Great Britain May 2, 1929.

will remain inoperative if temporarily energized from a source of current external to the remote control system. In this manner the two pilot wires are available for temporary borrowing for protective other purposes.

Thus such a remote control system may be employed in combination with protective gear for a feeder or like circuit lying adjacent to the remote control system, devices operated by the protective gear bein provided where py the two borrowable pilot wires are translerred when required from the remote control system to the protective system and are returned to their normal remote control connections as soon as their services are no longer required for the protective purposes. In such a combined arrangement a transfer d vice is preferably provided at each end of the protective system and when operated acts first of all to d sconnect the two pilot wires from the remote control system, one or each of the transfer devices then acting to connect the two pilot wires to a source of E. 11. F. associated with the protective system. One protective system, which is especially suitable for such combined service is that described in the United States Patent No. 1,765,887 standing in the names of one of the present applicants and another.

In order that any interruption from the protective system may not interfere with the process of selection, the transmission of selecting currents from the control station to the substation is conveniently carried out over the two unborrowable pilot wires. For corn trolling the selecting process, the arrangement forming the subject of United States Letters Patent No. 1,8203% standing in the names of one of the present applicants and another is preferably employed, wherein the apparatus at the control station controlling the transmission of a selecting current remains locked against further operation when such current has been transmitted until released by a current transmitted from the substation when the apparatus at the substation has correctly performed its selecting movement. This release current may be trans mitted over the two borrowable pilot wires to a release relay in the control station, such release relay being arranged to be responsive to the release current but to remain unaffected if temporarily energized from the source of E. M. F. associated with the protective system. Thus the protective source of E. M. F. and the source from which the release current is derived may both be D. C. sources, but may be so arranged as to be connected to the two pilot wires with opposite polarities, the release relay being polarized to be responsive only to the release current.

The system is preferably such that as soon as a selecting operation has beenperformed a circuit is completed over which a current is transmitted from the substation to the control station to give a supervisory indication as to the condition of the selected apparatus. Preferably one of the borrowable pilot wires is utilized in conjunction with one of the unborrowable pilot wires for carrying the supervisory indicating currents. With this arrangement means may be provided .vhereby, while supervisory indicating currents are flowing in the one borrowable pilot wire, a circuit including the other borrowable pilot wire is prepared over which alarm currents can be transmitted from the substation to give an alarm at the control station in the event of any change occurring automatically in the condition of the controlled substation apparatus. Such means may act on the disconnection of the two pilot wires by a transfer device to open the alarm circuit and thereby to prevent undesired operation of the alarm apparatus from the source of E. M. F. associated with the protective system.

Again means are preferably provided for establishing a clean circuit over the two unborrowable pilot wires for the transmission of metering currents from the substation to the control station. The metering circuit may be established by control station ap paratus which causes a current to be transmitted to a time-lag relay at the substation over one of the borrowable pilot wires and one of the unborrowable pilot wires. Conveniently the time-lag relay is connected across the two borrowable pilot wires and a quick-acting relay provided in the substation in series with the borrowable pilot wire utilized for the indicating circuits acts whenever current flowing in such pilot wire to disconnect the other borrow-able pilot wire from the time-lag relay. The control station apparatus which controls the transmission of current to the time-lag relay may be held locked in the event of temporary disconnection of the borrowable pilot wires be fore the complet. on of the time-lag of the relay, whereby the normal process of energizing such relay recommences immediately the pilot wires are restored.

The invention may be carried into practice in various ways, but the accompanying drawings illustrate by way of example a con venient arrangement according thereto,

'which the remote coi trol system is combined with a protective system of the kind described in the prior United States l atent- No. 1,765,887, above mentioned.

In these drawings,

Figure 1 is a circuit diagram of the substation apparatus, and

Figure is a similar diagram of the control station apparatus.

In this arrangement the control station and the substation connected together by four pilot wires A A A A which will for conveni nce be referred to respectively as the first, second, third and fourth pilot wires. The first and second pilot wires A A are so utilized in the remote control system that they can be borrowed temporarily for protective purposes without harmful interference with the remote control system, whilst the third and fourth pilot wires A A are retained exclusively for remote control purposes.

The protective gear new to be described is utilized for the protection of a feeder or like circuit B lying adjacent to the remote control system, such for example as a power feeder connecting the control station and the substation. It will be appreciated that t ere may be two or moreseparately protected feeder sections between tiie two stations, the protective gear for each secti' on being capable of borrowing portion of the first and second pilot wires A it? when required. For simplicity of description, however, will be assumed that a single feeder section extends from the control station to the substation.

The apparatus at the substation forming part of the protective is, with one exception to be referred to later, identical with that at the control station, and it is consequently only necessary to describe the apparatus at one end. in the drawings small reference letters are used to denote the control station protective apparatus, whilst corresponding capital letters denote the substat on protective apparatus.

The protected feeder B is provided at the substation end with two groups of relays, hereinafter referred to as the tripping relays diagrammatically indicated at C and the stabilizing relays diagrammatically indicated at D, each group containing overload and earth leakage relays arranged in the manner described in detail in the prior United States Patent No. 1,765,887 above mentioned. The stabilizing relays D are directional in operation, so that one or other of them will operate on the occurrence of a fault on the network provided that the current at the adjacent end of the feeder B is flowing outwards from the feeder, whilst the tripping relays C operate on the occurrence of a fault on the network irrespective of the direction of current flow in the feeder. The operation of any one of the stabilizing relay niote control circuits but after 0 Jeration of the relay disconnect tnezn rroin such circuits and connect them respectively to chan -ovcr contacts a on two sets oi the stain y a iXiliary relay E, and thence it the stab ing auxiliary relay has 1 atcd, to tire operating coil of loch-out .ay or if the stahiliziauxiliary l to the two sides loc part of the pix closed contacts G of t e ser with 1y open cont 0: t" relay F control a circuit tectrie battery ll 10 rec-tly control the clrci it-l th feeder B.

lhis un sccrnc pilot r l his LLl cause c1 9 it chi) r. i say tne suhstat hrs and second pilot Wires A i.

connectel the control station c lock-out I at the t end t i using c x.

from the substation loci:-

r'rezit Will s'ation to operate the CO? O.l

' g/ and thereby prov r the time-lag relay j at that substation.

e time he p subs:

an; i 17 Lplzo v n wi '1 r selves and return pilot Wires their norn'ial remote c protected at both ends.

7' Wlll reset thenr ler is cut out and )peraconnccteo. up again as soon the feeder is cut out at the supply end.

.l; it 'll be appreciatec that since the relays at he two ends operate independ e c .urtly, it may open that those at one end nay operate so the for a very brief interval, the loci:- G or g" or the local protective hatr it one end may be connected one end may be connected through the f0 pilot wires 21 11 to the remote control iatus at the other end. This cannot have effect on the operation of the cective system, unless it happens that at moment a battery in the remote control ein connected across the pilot Wires In such a case it might nappen that battery would cause incorrect operation r relay, which would delay (or from one end only the cutting out of the feeder guard against tiis, the protecnote control batteries at each end gee so they can only he lies with opposite out relays being polarized y' tocnrrcnt "rein the pr cattery. le clear later, the lar remote c system to be described is such thanv the control st? ion hattery can never be e ted across the first =13. second pilot win..- rl A Whilst it is po sihle tor the suhste ion battery under certain circumstances to he connected across them. Consequently it is dcsi able to polarize the loch-out relay at the control station end of the protective system, but is unnecessary to polarize the lock-out relay the substation end.

Before describing in detail the. arrangenent of the i iote control system, a brief description will be given of the general nature of the systen L t. robust mechanical rotary selector is employed at the sub-station, Which has a of positions each associated with an indr-widual substation apparatus, such for switch or circuit-hreal er, and c metering source, such as current iner, of which meter readings are to l thcontrol station. The rest of ec-iipinent is connnon to all .i oparatus ls aton cc; A

of individual meters to c with the corresponding substation sources. The connections to the meters at the control station are controlled by a mechanical. rotary s lector which also coopcrates With indicating mechanism for giving selective indications the control station oi the condition of selected substation apparatus. The two selectors have corresponding step-l ovements imparted to them,

l 't to movement consists of the the selectors from any one sen into the next. Each selecting initiated by operation of a sinand one e mi 'e nent it looted po '0 in ovemer gle selectio a ch of the push-button type the control 1011. In order to ensure accurate correspondence of movement between two selectors, the arrangement described in the United States Letters Patent 0. 1,820,35 above mentioned is employed, wherein the control station selector makes two halt-notch movements r each full-notch movement the substation selector during each sole: movement. Thus when the N 1 LR, sei cc-ci pl 1 EiltlOl'l, th o \n 1 \,1LO1(l s ransmitted to the subsolenoid operated its full-notch selecting move nent into t is net SoiQCll-Qd position. As soon as the no vement of the substation selector is cc-mp;eted, release current is transcontrol station to energize a re j and thereby to operate a second renoid which re.

ained locked v: to the selector in its half- 1 'on) subsequent y causes the tion selector to perform its second movement. This completes the con rol t again operate his selecting the next substation apparatus supervisory indication, and so posi ion, the operator may, of performing a "further an ezzecutive ausingsome operation to be ion apparaclosing switch circuit-breaker) or he may operate meter switch for c using establishment of the metering circut over which reada L ings can b6 btlnfill 2o toe control tation of the metering source associated with the selectel position. Depression of executive push causes an executive curren transmitted over the same circuit as the selecting currents,

but with a polarity opposite to that of a selecting current, a polarized relay in the substation effecting the necessary discrimination between the two kinds of current. When the executive function has been performed in the substation by suitable apparatus, the supervisory indicating circuit is reestablished and an indication of the changed condition of the substation apparatus is obtained at the control station, the Whole system a 'ain coming to rest in a condition ready Ior a new selecting movement or the establishment of the metering circuit. it new, the operator operates his meter switch (for instance by a rotary movement through 180) suitable apparatus will cause the establishment of the metering circuit from the sele ted substation metering source to the correspon ing control station meter, and the system will remain at rest i the metering condition, until the meter snitch is operated ("for instance by acontinued rotary movement through a further 18f) when the system Will revert to its normal c'i lition in the selected position with the supervisory indicating circuit completed.

The normal Zero position ot the selectors is reserved for S3C1Etl pur Joses, such as the establishment of communication sion from the substation or general alarm some cha ge has current indicate that talren ace ant 'ly in toe condition of the substation co fed apparatus. Pro vision is also made for the smission of a to attend to the general alarm signal he will see the condition or all. the substation appara- I w -1 tus and Wlll at once knew of the automatic change which brought about the general a arm The autonn 51c CLlC cycle is not however performed in the event n 1 I l w re gener al alarm sip our Peeing transmitted ml stthe selectors i any position other than the normal Zero .sn icn.

I, 1, i- J; V i. Altnough or nnarily the system is suc each selecting movement is initiates oy a separate d pre slon of the selecting means preferably provided operator may effect exoress selection, i. e. movement through number of selected positions Without repeat-ed depression of the selecting push. Such eXp-ess selection consists in the automatic initiation of a further selecting movement imi rediatelv a previous one is i I 1 r completed as iar as the desired selected posiby a solenoid 21.

so In the l eaker 101'. that associa c with the seconu tion, but it wi be a 'u reciated that there will in practice he a number oi such circuit-breakers or other apparatus each associated with an individual selected position. The circuitbrealrer l) is shown op n by way of example,

7 is provided with a closing coil 11, a. tripcoil 12, and si auxiliary switches 18 which are operated by the movement of the circuit-breaker from its open to its closed position or vice versa. The auxiliary switch is a late-acting switch which is closed when the circuitbreaher 10 is open and opens just before the circuit-breaker closes: The auxiliary switch 16 is a flick switch, i. e. one which closes momentarily and opens a 'ain during the closing or openingmcveir of the circuit-breaker10. The second selected position is also associated with source, indicated by way of example as a current transformer 19.

The substation rotary selector is indicated at 20 and is driven through its step-by-step movements by ratchet mechanism operated Contacts 2225 are provided which are operated by the selector actuating mechanism during each selecting movement in such a manner that the contacts 22, 24 are closed and the contacts 23, 25 opened immediately the selector completes its movement into a new selected position, the tour contacts being brought back again to the condition shown when the selector solenoid 21 is deencrgized and its mechanism resets. These contacts control the transmission to the control station over the pilot wires A A of the release current above mentioned. The selector :20 has groups of contacts associated With its various positions. Thus the contacts A one controlled circuitio' n at the substation, namely 1 selected posi- -37 are associated with the normal zero position and are changed over from the condition shown as soon as the selector leaves this position. These contacts reassume the condition shown when a complete selecting cycle has been performed and the selector '11 returns to the Zero position. The contacts l0-l7 are associated with the second st ected posi ion (i. with the particular circuitbroalrer 10 and currenttrans-former shown in the drawings, and are changed r when the selector moves into the second tion. These contacts remain in the confon shown in all selector positions other i n the second. Similar groups of contacts (not shown) are provided on the selector for other selected positions. These groups of contacts together with the corresponding circuit-breaker auxiliary switches control the connections between busbars common to all the controlled apparatus and a battery provided in the substation for the operation of various parts of the remote control equipment. The connections to the two poles of the battery are controlled respectively by contacts 55, 56 on a locleout switch 57, which also has contacts 51, 52, 53, 54 respectively controlling the four pilot wires A A A A at the substation end, whereby the substation remote control equipment can be cut off from the pilot wires and the battery for inspection and repair purposes.

The positive pole of the battery 50 is con nected through the lock-out contact 56 to the positive busbar 60, and the negative pole is connected through the contact to the negative busbar 61 and also to the selector contacts 40, 41, 42, which are closed only in the selected position. The contacts 40 are connected on the other side to the circuit-breaker closing coil 11 and thence to a closing busbar 65, the contacts 41 being similarly connected through the circuit-breaker auxiliary switches 13 and 14 respectively to a close relay busbar 67 and a trip relay busbar 68, Whilst the contacts 42 are connected through the trip coil 12 to a tripping busbar 66 and through the auxiliary switch 15 to an executive relay retaining busbar 69. The positive busbar is connected to the flick switch 16 and thence either through the selector contacts 44 (closed in all positions except the selected position) to a general alarm busbar 70 or through the selector contacts l3 (closed only in the selected position) to an auxiliary general alarm busbar 71. The selector contacts 4:5, 46 (closed only in the selected position) control the connections from two indieating busbars 75, 76 to the contact arms of the circuit-breaker auxiliary change-over switches 17, 18 and thence to one or other of the positive and negative busbars 60, 61, the two indicating busbars thus being oppositely energized with a polarit 1 dependent on whether the selected circuit-breaker is closed or open. The selector contacts 47 are closed only in the selected position and are in series wit 1 the metering source 19 between two metering busbars 77, 78. The connections of these busbars to the other parts of the remote control equipment will be described later.

The principal relays in the substation remote control equipment are an executive relay 80 with contacts 8185 controlling the performance of executive functions; a selector relay with contacts 91-94 controlling the operation of the selector 20; a polarized relay 100 having contacts 101 and 102 respectively controlling the energization from the substation battery 50 of the selector relay and the executive relay, this polarized relay being energized by currents of one polarity or the other sent from the control station over the third and fourth pilot wires if A; two meter relays 110, 120 respectively with contacts 111-117 and 121129 for control ling the establishment of a metering circuit, the normally open contact 128 being arranged to close before the opening of the contact 127 when the relay is energized; an auxiliary indication. relay 130 with contacts 181, 132 whose function will be described later; a release meter relay 135 with contacts 136-138, of which the normally open contacts 137 are arranged to close before the opening of contact 138 when the relay is energized; a trip relay 140 with contacts 14114 1 and a close relay 145 with contacts 1 16-1 18 operated by the executive relay 80 for controlling the tripping and closing of selected circuitbrealrers; and a general alarm relay 150 with contacts 151-155 having associated with it a definite time limit relay 156 with its contact 157 for controlling the transmission of gen eral alarm signals to the control station.

The substation is also provided with a telehone 160 having the usual receiver hook switch 161 and calling bell 162 and with a telephone push 165 having contacts 166-168 for controlling the transmission of a telephone calling current to the control station. The telephone push 165 is locked against operation in all selector positions other thanthe normal zero position by an electromagnetic locking device 169 energized over a circuit including the selector contacts which are closed in all positions except the zero position. The indicating circuit and the metering circuit (to be described later) are utilized in the normal zero position for carrying the telephone calling signal from the substation to the control station and the telephone speaking currents, the general alarm signal (which is of opposite polarity to the telephone calling signal) also being transmitted over the indicating circuit in this position. For this purpose, the telephone push contacts 167, 168 are arranged as change-over contacts in series with the selector contacts 33, 84. (closed only in the zero position) and control the connections of the indicating busbars 76, to the positive and negative busbars 60, 61 in a manner similar to that of the circuit-breaker auxiliary switches 17, 18, whilst the telephone 160 is in series with the selector contacts 37 closed only in the zero position between the two meteringbnsbars T4178.

The indicating busbar 76 is connected through the normally closed contacts 93 and 127 of the selector relay 90 and the second meter relay 120 and the lock-out contact 5 1 to the fourth pilot wire A The other indieating busbar 75 is connected, when the selector is in any position other than the zero position, through the selector contacts 31 and the normally closed contact 124: on the second meter relay 120 to one side of the auxiliary indication relay 130, the other side of which is connected through the contact 25 on the selector actuating mechanism, the lock-out contact the contact F of the protective tripping auxiliary relay F to the second pilot wire A The connection between the second and fourth pilot wires A A through the indicating apparatus at the control station will be described later. It will be noticed that whenever indicating currents are flowing over this indicating circuit the auxiliary indication vrelay 130 will be energized. The connection of the indicating busbar 75 to the auxiliary indication relay 130 when the selector is in its normal zero position is taken through the selector contacts 82 and thence, if the telephone push 165 is depressed, through its contact 166, or, if the general alarm relay 150 has operated, through its contact 152, but the circuit is incomplete in the normal zero position unless either the telephone push or the general alarm relay has been operated. The operation of the general alarm relay 150 also closes contact 155 and thus completes a connection from the indicating busbar 7 5 to the first pilot wire A (through contacts 23, 51 and F provided that either the auxiliary indication relay 130 is energizes to close its contact 132 or the second meter relay 120 is energized to close its contact 125. I

The metering busbar 78 is directly connected to the fourth pilot wire A through the look-out contact 54. The metering busbar 77 is connected to the third pilot wire A" through the normally closed contacts 81, 151 and 111 respectively on the executive relay, the general alarm relay and the first meter relay and through the contact 121 (which is closed when the second meter relay operates) and the lock-out contact 53. The manner in which the second meter relay 120 is energized to complete the metering circuit at contact 121 will be described later.

The polarized relay 100 is connected between the third and fourth pilot wires A A through the look-out contacts 53, 5 1 and the contacts 127 and 136 on the second meter relay and the release meter relay, and is con sequently capable of receiving currents of either polarity sent from the control station over these pilot wires for selecting or executive purposes. Thus when a selecting current is received the polarized relay will close its contacts 101 and energize the selector relay 90, which breaks the indicating circuit at contact 98 and completes the energizing circuit to the selector solenoid 21 at contact 92. An executive current on the other hand will cause the energization at contacts 102 of the executive relay 80. The function performed by the executive relay depends upon the position occupied by the selector at the time and also on the condition of the selected apparzn tus. Thus it the sel ctor is in a position associated ci c 'te e tive r'lay c 1.5 in acc circt i selector 1' relay will second in t1 lish the m J. r tele i lector co ta ts :ecutive rea S is operated for circuithrcalrcr closing purposes, it completes its own retaining cir This tilt at contact 85. circuit is tzlrcn "from the negative pole or tt-ery 50 tnrough the look-out con' sclecto tacts 4:2 in the appropria selector p the late-acting auxiliary switch '3 selected circuit-breaker (issuer c L a 69 the t y or ntact ki l, the selector reche cnecutive relay contact 1,19 operating coil of the the other *ide of which is of the .ct 56. stains itself cner y of the polarized relay ning circuit is broken by switch when the selected circuit retaining circuit J to; circuit-breaker tripping to the very short time r quired to C0111" l e the tripping operation.

The energizin. c'

lay contact 85 to one closing;- n ov hrcalzcr is co is unnecess purposes k u'cuit of the trip elay 1 10 is taken from 1 positive pole of the hattery through tlie loch-ontcontact 56, the executive relay contact and an interlock contact 1&8 close relay 14-5 to one side of the trip relay coil, the other side o'l which is connected to the trip relay husbar 68 ar c thence through the au .iary switch i l of ti elected circtut-breaker 10, the corresponcin selector contact 1-1 and the lock-out contac F5 to the n ire pole of the battery 50. The enc icing circuit of the close relay 1 .5 is taken LOll'l the positive pole of the battery 50 throi oh the loclnout contact 56 the executive relay contact 84: and an interlock con tact ill; on the trip relx 1 10 to one side of the close relay coil, th er side of whicl is con cctcd to the cl i i thence through the auii'liar switch 13 on the in cc'wl sition either the trip relay 7- v r clay will he ei'ierg'ized 111 r .e v iether the selected circuit- 1 L0 is ciose'l or open. The trip relay 140 makes its own retaining circuit at contact 143 to prevent its deenergization (and the consequent energization. of the close relay 145 if the executive relay is still energized) when the circuit-hr alter is tripped and the atxiliary switches 13 ll change over, the close relay 1%? being provided to the hattery 50. The close relay 145 at its conta t 1426 energizes t-l closlng; coil 11 "eak i over a similar he closing hushar and contacts 40 instead of the trippinp; hushar 66 and the selector contacts 4-2.

The first meter relay 110, which has a short time lag, is connected on one side to the first pilot wire A through the normally closed contacts 131 and 123 on the auxiliary indica-- tion relay and the second meter relay and on the other side to the second pilot wire A throug the ooerating coil of the auxiliary indica on relay 130 (these connections also including the contacts 23, 25 the selector actuating mechanism, the lock-out contacts and the protective tripping auxiliary relay contacts F F Thus so long as indicating currents are flowing in the second pilot wire A this meter relay is cut out of circuit by th auxiliary indication relay contacts 131. e opening of the second pilot wire circuit and the temporary connection of the and fourth pilot wires together at the control station wh the indicating currents c c circuit including t L J. toe selector e Tl flowing (which as vill he Xplained later the procedure adopted for the establishc of :i meteringcircuit in a selected posiwill deenergize he auxiliary indicarclay 180 and divert the indicating curents through the first meter relay 110, and th s relay to close its contact he second meter relay over of the re- .y 120 makes 115 t 12% and 16 normal c, an

st in eter ey 110, energised through his ntil the cir cu. olicn at cinitroi eta: cl o'l? cortacts 111 an 12 shment of he metering Huh. lotion end fl 1 r01 toe for operation when ergized whenever a circuit-breaker changes its condition (owing to the momctary closing of the flick tch 16) unless sol c or in pct correspondir such circuit-breaker, the selector contacts at being then open. I" in any selector pos breaker associate 1 its condition automat relay 15 the positive busbar 60, through the dick switch 16, the selector contacts a3, the aux;- iliary alarm busbar 71, the second meter relay contact (now closed) and the general alarm relay 150 to the negative busbar 61. The general alarm relay makes its own retaining circuit at contact 154 through the contact 157 of th' definite time limit relay 156, which is simultaneously energized at contact 153 over circuit including interlock contacts 114, 91 and 82 on the first meter relay, the selector relay and the executive relay. The definite time limit relay 156 acts to open the circuit of the general alarm relay after a predetermined time interval. The object of this is to put the ge eral alarm relay 150 in readiness for transmitting a further general alarm signal if necessary in the event of the system being a in any position other than the normal Zero position, for example whilst metering is in progress.

The control station remote control equipment will now be described.

The supervisory indicating currents, which are transmitted from the substation over the second and fourth pilot wires i A received by apolarized indication relay 200, which is connected between these two pilot wires through certain interlock contacts to be described. This relay 200 operates one or other of two sets of contacts 201, 202 in accordance with the polarity of the indicating current received and tnereby energizes either a positive coil 210 or a negative coil 215 respectively operating contacts 211-213 and 216-218. Although indicated on the drawings as separate relays, these two coils 210, 215 preferably act on a common armature whose movement in one direction or the other operates suitable indicating mechanism which may for instance take one or other of the forms described in the United States Let ters Patent No. 1,820,35a' standing in the names or" one of the present applicants and another. A contact indicated at 205 is operated by tie indicating mechanism when the desired indication has een given. The constructions of indicating mechanism described in the prior United States patent referred to include in addition to the common armature of the coils 210, 215 a group of indicators respectively corresponding to the individual suostation circuit-breakers 10 or other apparatus, and the determination as to which circuit-breaker has been selected (and on when the circuitwitn such position changes ically, the general alarm 'ill be energized over a circuit from metering is in progress,

to those of the substation selector 20. As

will be described in detail later the selector 220 performs two separate half-notch movements for each full-notch movement of the substation selector 20 in the manner described in the United States Patent No. 1,320,35a above mentioned, the halfnotch movement being controlled by a first motion solenoid 221 and the second halfnotch movement by a second motion solenoid 222, which is in turn controlled by a polarized release relay 223 having contacts 224-. The selector 220 has groups of contacts 230-232, 23 /Vhich are operated in its various positions. Thus the contacts 230 are closed in the first few (say four) selector positions and are open in all other positions; the con tacts 231 are closed in the normal zero position and open in all other positions; the conacts 232 are closed in all positions other ran the normal Zero position; the contacts 3 are closed only in the second position. he selector also carries a cam indicated at 5, which operates a contact rod 226 having ntacts 227, 228, the arrangement being such that the contacts 227, 228 are open in the first few posit-ions and close before the contacts 230 open, remaining closed from, say, the third position to the last position. The selector actuating mechanism operated by the solenoids 221, 222 also serves to operate contacts 240-2 18 at various stages in the sequence of operations constituting a selecting movement from one position to the next, as will be described in detail later. i

A local battery 250 is provided in the control station, the connection to its two terminals being controlled by contacts 255, 256 on a lockout switch 257 also having contacts 251, 252, 253, 254 respectively controlling the connections of the four pilot wires A A A A to the control station remote control equipment, the general arrangement being similar to that of the lock-out switch 5'? at the substation. The positive pole of the bat tery 250 is connected through the lock-out contact 255 to a positive busbar 260 and the negative pole is connected through the contact 256 to a negative busbar 261. A meter- This push is of special construction to enable it either to be depressed and released for the purpose of initiating a simple selecting movement from one position to the next or to be depressed and rotated (whereby it is held in the depressed condition until released by a return movement) for the purpose of initiating an express selecting movement through a series of successive simple selecting movements from any one position to any other position. The contacts 271, 273, 274 are operated by depression of the push and remain in their operative positions when the push is rotated, whilst the contact 272 remains inoperative unless the push is rotated.

The performance of executive functions in the substation in any selected position is ini tiated by means of a trip push 280 and a close push 290, which have similarly arranged contacts 281-285 and 291-295 respectively. The contacts 281, 282, 285 or the contacts 291, 292, 295 serve when the corresponding push is operated to break the normal connections of the pilot wires A A A all of which are normally connected directly or indirectly to the positive busbar 260, whilst the contacts 284, 294 serve to make a connection from the negative busbar 261 through the contact 244 on the selector actuating mechanism to the pilot Wire A', and the contacts 283, 293 make a similar connection from the positive busbar 260 through the selector actuating mechanism contact 2 13 to the pilot wire A The establishment of a metering circuit in any selected position is initiated at the control station by a rotary meter switch 300 having contacts 301 309. This meter switch may be constructed and arranged in a manner similar to that described in British Patent No. 310,984. Contacts 301, 306 and 309 are normally closed and control the normal connections to the pilot wires A A and A respectively. To establish the metering circuit the switch. 300 is rotated through 180. The first movement of the switch opens contacts 301 and 306, and shortly afterwards, say at about 90 rotation, the contact 303 closes for a brief interval and opens again. Contact 304 opens approximately at the 120 position. When the 180 position is reached the contacts 302 and 308 close, the contact 308 making a direct connection from; the metering busbar 262 through the lock-out contact 253 to the third pilot wire A The other side of the selected meter is connected through part of the positive busbar 260 to the fourth pilot wire A through various closed contacts including the contact 309. When it is desired to open. the metering circuit, the meter switch 300 is rotated further, its first action being to disconnect the selected meter from the pilot wires by opening contacts 308 and 309, contact 302 also being opened. At or about 270 the contacts 305, 307 are closed and opened, the contact 305 serving to make a connection from the negative busbar 261 through contact 244 to the second pilot wire A whilst the contact 307 connects the positive busbar 260 through contact 243 to the third pilot wire, whereby a momentary current is transmitted over these pilot wires to the substation for the energization of the release meter relay 135. The completion of the 360 movement of the meter switch recloses contacts 301, 1, 306, 309 and thus brings the circuits back to the normal condition.

As will be explained in detail later the temporary closing of the contact 303 at the 90 position causes the energization of the first meter relay 110 at the substation and since this relay has a slight time-lag it is necessary to arrange that the contact 303 remains closed for a suflicient time. For this purpose an auxiliary meter relay 310 is provided in series with the contact 303, the normally open contact 311 of this relay controlling the energizing circuit of a time-lag electromagnetic locking device 315 acting on a projection diagrammatically shown at 316 on the meter switch 300, the arrangement being such that the lock is normally applied and is released when the coil 315 has been energized for a time interval equal to the time-lag of the substation first meter relay 110. This locking device is provided with a contact 317 in series with the meter switch contact 304 to retain the coil 315 energized until the meter switch has passed the 120 position.

The establishment of telephone communication between the two stations is initiated by a dummy push 320 operated by lifting the telephone instrument. This push has contacts 321-326, two of which 322, 326 are normally closed and control the connections to the pilot wires A A The first movement of the dummy push 320 opens these two con tacts 322, 326, shortly after which the contacts 32 1, 325 close and open again to trans mit a momentary current from the control station battery over the pilot wires A A similar to that transmitted by the operation 01" the trip and close pushes. The completion of the movement of the push 320 closes contact 323 and recloses contact 326, thereby connecting the telephone instrument 330 across the pilot wires A A through various closed contacts including a contact 3 11 on a zero position relay 340, which is energized through the selector contacts 231 closed only in the normal zero position. During the return movement of the dummy push 320, after the telephone conversation has been completed, the contacts go through the reverse movements with the exception that contact 325 is inoperative and contact 321 (which was inoperative during the forward movement) closes and opens simultaneously with contact 324.

The zero position relay 3 10 has in addition to the contact 341 four other contacts 342- 3 15, all of which are closed when the relay is energized, i. e. when the selector is at rest in the zero position. The telephone buzzer 331, with which a red lamp 332 is in parallel, is energized when the polarized relay 200 causes the positive coil 210 to close its contact 212, this energizing circuit including the contact 3% on the zero position relay 340. The energization of the positive coil simultaneously opens contact 211 and thereby breaks a normally closed circuit, including contacts 216 and 3 12, to a green lamp The buzzer 331 and red lamp 332 are also utilized for giving the general alarm signal under the control of two general alarm relays 350, 355, the contact 356 of the latter relay directly controlling'the buzzer circuit. The main general alarm relay 350 is connected between the first and fourth pilot wires A A through various contacts, this connection being completed in various circumstances by the contacts 213, 213 and 302;

Thus when the system is at rest in the normal zero position the contact 218 closes to complete this connection when the polarized relay 200 receives a general alarm signal, and similarly when the system is in any other selected position and a supervisory indicating current is flowing one or other of the contacts 213, 213 will be closed in accordance with the polarity of the indicating current, whilst when a metering circuit is established in any position the contact 302 will be ,closed. This general alarm relay 350 is energized by a general alarm signal transmitted from the substation over the pilot wires A A and its contact 351 controls the energizing circuit of the auxiliary general alarm relay 355, which besides closing the contact 353 in the buzzer circuit makes at contact 357 its own retaining circuit through a normally closed contact 337 on a stop alarm push 335 having a further contact 333 and through a normally closed contact 365 on an auxiliary reindication relay 360. This relay 360 has four other contacts 36136& and its energizing circuit is controlled by the contact 371 of a general reindication relay 370 havingother contacts 372-37 1.

The two reindication relays 360, 370 are utilized for causing a complete selecting and indicating cycle to be performed automatically when a general alarm signal is received from the substation while the system is at rest in the normal zero position, and it is necessary for this purpose for the indicating mechanism controlledby the positive and negative coils 210, 215 to be of the self-recording type. The reception of a general.

alarm signal under these circumstances causes contact 217 to close and thereby to complete a circuit through the contact 3 1 3 to the general reindication relay 370, which makes its own retaining circuit at contact 372 through the selector contacts 230 which are closed in the first four selector positions. Contacts 373, 37 1 respectively bridge the selecting push contacts 273, 274, and Contact 371 completes the circuit to the auxiliary relay 360. This relay makes its own retaining circuit at contact 361 through the selector contacts 232 closed in all positions except the zero position, and also through a further circuit including the selector push contact 271 and the stop alarm push contact The contact 365 opens to deenergize the auxiliary general alarm relay 355 and the contacts 353, 364 in series with the camoperated contacts 227, 223 makes further bridging connections across the selecting push contacts 273, 274 after the third position is reached.

The operation of the remote control system will now be described first of all'with reference to the performance of a selecting movement from one selector position to the next.

When the system is at rest in the normal zero position as shown all the remote control equipment is deenergized with the exception of the zero position relay 3 10, which is energized over a circuit from the control station positive busbar 260, through the contact 243 on the selector actuating mechanism, the relay 3&0 and the selector contacts 231 to the negative busbar 261.

On the other hand when the system is at rest in any other position, a supervisory indicating current is flowing over the indicating circuit which is taken (assuming for example that the selectors are in the second position corresponding to the open circuit-' breaker 10 shown in the drawings) from the substation negative busbar 61 through the circuit-breaker auxiliary change-over switch 17, the substation selector contacts 45, the indicating busbar 75, the selector contacts 31 (now closed), the contact 124, the auxiliary indication relay 130, the contacts 25, 52, F the pilot wire A the contacts F, 252, 282, 292, 303, 322, the polarized indication relay 200, the contacts 241, 326, 309, 295, 285, 25 1, the pilot'wire A the contacts 5a, 127, 93, the indicating busbar 76, theselector contacts 426 andthe auxiliary change-over switch 18 to the positive busbar 60. Thus the auxiliary indication relay 130 is energized, and the polarized indication relay 200 is also energized to close its contacts 202, whereby the indicating mechanism is giving the correct out indication and the contacts 216, 217, 218 and 205 are operated. The rest of the equipment is deenergized.

It now it is desired to efiect a selecting movement from one position to the next, the selecting push 270 is depressed to close contact 27 1. This completes the circuit to the first motion solenoid 221 from the negative busba r 261, through the selector actuating mechanism contact 248, thesolenoid 221 and the selecting push contact 274, and thence either through the contact 345 or the contact 205 (according to whether the selectors are in the zero or in any other position) to the positive busbar 260. The movement of the armature of the solenoid 221 first opens contacts 240, 241, 243, 244 and closes contact 247 (thus opening the above-traced indicating circuit at contact 241 and closing a retaining circuit for the solenoid 221 independent of the selector push which may now be released), and then, besides driving the selector 220 to its first half-notch position, closes contacts 242, 245, 246 and opens contact 248. Contacts 245, 246 prepare the circuit for the release relay 223 to be referred to shortly, and contact 248 deenergizes the first motion solenoid 221, the control station equipment now remaining locked against further operation with the selector in its half-notch posi tion until the reception of a release current from the substation. The closing of contact 242 completes the circuit for the transmission of a selecting current to the substation, this circuit being taken from the control station positive busbar 260 through the contacts 326., 309, 295, 285, 254, the pilot Wire A*, the con tacts 54, 127, 136, the substation polarized relay 100, the contact 53, the pilot wire A and the contacts 253, 242 to the negative busbar 261. The polarity of this current is such as to operate the polarized relay 100 in the selecting direction to close its contacts 101 and energize the selector relay 90. This relay 90 again breaks the indicating circuit at contact 93 and closes contact 92 to energize the substation selector solenoid 21. The movement of the solenoid armature then drives the substation selector to its new position, and when this position is reached opens contacts 23, 25 and closes contacts 22, 24. This completes the release circuit from the substation negative busbar 61 through the contacts 22, 51, F the pilot wire A the contacts F, 251, 281, 291, 301, 245, the polarized release relay 223, the contacts 246, 273 (closed it the selecting push has meanwhile been released) the contacts 322, 306, 292, 282, 252, F, the pile wire A and the contacts F 52, 24 to the positive busbar 60. Thus provided the selecting push 270 has been released, the release relay 223 is energized to close its contacts 224 and energize the second motion solenoid 222. The consequent upward movement of the armature of the solenoid 222 prepares the pawl and ratchet mechanism for driving the selector through its second half-notch movement and also opens contact 242 to break the selecting circuit and thereby to deenergize the substation polarized relay 100 and the selector relay 90. This restablishes the indicating circuit at the substation end at contact 93 and deenergizes the substation selector solenoid 21, whose mechanism resets and opens contacts 22, 24 closing contacts 23, 25. The opening of contacts 22, 24 breaks the release circuit and consequently deenergizes the release relay 223 and the second motion solenoid 222, whose armature moves back under the action of a spring and drives the selector through its second half-notch movement, resetting contacts 240, 241, 243, 244, 245, 246, 247, 248. The whole system is now at rest in the new selected position with the indicating circuit completed to give a supervisory indication of the newly selected circuit-breaker.

If, instead of performing a single selecting movement, the operator wishes to perform an express selecting movement through a series of selector positions, the only difference in the above operation will be that the selecting push 270 will be depressed and rotated instead of depressed and released. This rotation of the push causes contact 272 to close, so that the release circuit is complete at the appropriate stage without the necessity of releasing the push to close contact 273. The whole selecting movement will thus be carried out as above described, but at the end a new selecting movement will automatically be started immediately the indicating mechanism closes the contact 205, since the selecting push contact 274 is held closed. Thus the selectors will automatically continue to step round from position to position. giving the desired supervisory indication in each position, until the operator releases the selecting push 270 when the se lecting movement in progress at the time will be completed and the system will come to rest in the desired selected position with the supervisory indicating circuit complete.

In any selected position the operator may if he wishes transmit an executive current to cause the performance of some operation on the selected apparatus at the substation. Thus if the selected apparatus happens to be an open circuit-breaker, he may depress his close push 290 to effect closing of the circuit-breaker, or if the selected circuitbreaker is closed depression of the trip push 280 will cause it to be tripped. The manner in which operation of the trip and close pushes causes the desired operation to be performed will now be described. The contacts of the two pushes are similarly arranged and the effect of depressing either of them is to open the first, second and fourth pilot wires A A A at contacts 281, 282, 285 or 291, 292, 295, thus breaking the indicating circuit, and to connect the third and fourth pilot wires A A to the two poles of the control station battery at contacts 283, 284, or 293, 294. This energizes the substation polarized relay 100 with a polarity opposite to that of the selecting currents over a circuit from the control station negative busbar 261 through the contacts 244, 284 (or 294), 254, the pilot wire A, the contacts 54,

127, 136 thepolarized relay 100, the contact 53, the pilot wire A and tie contacts 253, 283 (or 293) 243, to the positive busbar 260. The polarized relay 100 consequently closes its contacts 102 and energizes the executive relay 80. It the selected circuit-breaker happens to be open (the operation of the execu tive relay then being due to the depression of the close aush 290), the executive relay makes its own retaining circuit at contact 85, and at contact 84 makes the energizingcircuit for the trip relay 140 or the close relay 145 as the case may be, these relays in turn etl'ecting the tripping or closing of the selected circuit-breaker in the manner above described. Release of the trip or close push at the control station then reestablishes the indicating circuit, whereby the control station operator is advised as to whether or not the executive function has been correctly performed.

The establishment of the metering circuit in any selected position (other than the normal zero position) is initiated by rotation of the meter switch 300 through 180. This first opens the indicating circuit at contact 306 and thus ale-energizes the auxiliary indication relay 130 which closes its contact 131. When the meter switch reaches the position contact 303 closes momentarily. This completes a circuit (assuming for example that the circuit-breaker associated with the selected position is closed) from the substation negative busbar 61 through the auxiliary switch 18, the selector contacts 46, the indicating busbar 76, the contacts 93, 127, 54, the pilot wire A the contacts 254, 285, 295, 309, 326, the auxiliary meter relay 310, the contacts 303, 251, P, the pilot wire A the contacts F 51, 23, 131, 123, the first meter relay 110 and the contacts 124, 31, 45, 17 to the positive busbar 60. This at once operates the auxiliary meter relay 310 to energize the electromagnetic locking device 315 and also energizes the first meter relay 110. At the expiration of its brief timelag this relay operates its contacts. The closing of the contact 115 energizes the second meter relay 120 which retains itself at contact 128 and opens contacts 123, 124, 127 in the energizing circuit of the first meter relay 110, which however, remains energized owing to the closing of its contacts 112, 113, 116. The electromagnetic lociiing device 315 at the control station has meanwhile unlocked the meter switch 300 and the continuation or" the movement of this switch past the 90 position opens contact 303 and thereby deenergizes the auxiliary meter relay 310 and the substation first meter relay 110. The opening of contact 116 breaks the connection between the polarized relay 100 and the pilot wire A contact 127 now being open, and the closing of contact 117m series with contact 129 (now closed) connects the release meter relay 135 across the pilot wires A A in preparation for the opening of the meter circuit later. The closing oi contact 111 in series with contact 121 (now closed) prepares the metering circuit at the substantion end,and the completion of the movement of the'meter switch 300 into the 180 position establishes the metering circuit at contact 308. This metering circuit is taken from one side of the selected metering source 19 through the metering busbar 77, the contacts 81, 151, 111, 121, 53, the pilot wire A the contacts 253, 308, the busbar 262, the selected meter 265, the selector contacts 233, the busbar 260, the contacts 326, 309, 295, 285, 254, the pilot wire A the contact 54, the metering busbar 78 and the selector contacts 47 to the other side of the metering source 19. It will be noted that the meter'switch contact 302 is closed at this stage for general alarm purposes as will be explained later.

When themeter switch 300 is rotated further, in order to open the metering circuit, its first action is to disconnect the control station meter 265 from the pilot wires at contacts 308, 309, and it then momentarily closes contacts 305, 307 to send acurrent over the pilot wires A A? for the energization of the release meter relay 135, this circuit being taken from the control station positive busbar 260 through the contacts 243, 307, 253, the

pilot wire A the contacts 53, 117, 129, the release met-er relay 135, the contacts 52, Ffithe pilot wire A and the contacts F, 252, 305, 244 to the negative busbar 261. The release meter relay 135 makes its own retaining circuit at contact 137 and again breaks the connection of the polarized relay 100 to the pilot wire A", whilst the opening of the contact 138 breaks the retaining circuit for the relay 120 which is consequently deenergized. This reestablishes the normal conditions in the selected position in the substation (except for the deenergization of the release meter relay) and the completion of the movement of the meter switch to its 360 position performs the corresponding function at the control station, and also breaks the circuit to the release meter relay, so that the whole system is new again at rest in the selected position with the indicating circuit closed.

Telephone communication can be established between the two stations when the system is at rest in the normal zero position. If the'control station operator wishes to call 1p the substation he lifts his telephone instrument and thereby operates the telephone dummy push 320. This first breaks the second and fourth pilot wire circuits at contacts 322, 326, and then momentarily closes contacts 324, 325 to transmit a current similar to the executive currents to the control station, its final movement closing contact 323 and reclosing contact 326. The momentary executive current energizes the substation polarized relay 100-in a direction to close its contacts 102 and thereby to energize the executive relay 80. The closing of contact 83 energizcsthe second meter relay 120 over a circuit including the selector contacts closed only in the normal zero position. This relay 120 makes its own retaining circuit at contact 128 before. so that it remains energized when the executive relay is decnergized the result of the deenergization of the polarized relay 100 when contact 127 opens. and the closing of contact 129 prepares the circuit for the release meter re ay 135. The contact 121 on the second meter relay 1,20 prepares the metering circuit for the transmission of the telephone speaking currents. and th contact 122 closes a circuit to the substation telephone call bell 162 through the hook switch 161 and the selector contacts 36. ld hen the substation operator responds to the call and lifts his receiver. the hook switch 161 breaks th calling circuit and the speaking circuit is now complete. this circuit extending from the substation telephone 160 through the contacts 81 (now again closed), 151. 111, 121, 53, the pilot wire A the contacts 253, 323, 34-1, the control station telephone 330, the contacts 326, 309. 295. 254, the pilot wire A and the contacts 54. 37 back to the substation telephone. When the call is finished the control station operator replaces his instrument and the dummy push is released, first opening contacts 323, 326, then closing and opening contacts 321. 324 and finally closing contacts 322. The momen tary closing of contacts 321. 324 sends a current over the pilot wires A A to ei'iergize the release meter relay and thereby to deenergize the second meter relay 120. the whole system then returning to its normal condition.

It the substation operator wishes to call up the control station when the system is in the zero position, he depresses his telephone push 165. This causes a current similar to a circuit-breaker-closed indicating current to be transmitted over the indicating circuit. the connection from the indicating busbar 75 to the auxiliary indication relay 130 however being taken through the contacts 32. 166 instead of through the contacts 31. 124. The polarized relay 200 at the control station is thus energized to close its contacts 201 and energize the coil 210. thereby closing the circuit to the buzzer 331 at contact 212. On respondin to the call. the control station operator lifts his instrument and operates the substation call bell in the manner above described, whereupon the substation operator lifts his receiver and coimnunicatioii is established.

The general. alarm arrangements will now be described first of all with reference to the transmission of a general alarm signal when a change of condition of one of the substation apparatus occurs automatically while the system is at rest in the normal zero position. WVhen such a change occurs the flick switch 16 on the circuit-breaker which has operated (or an equivalent device in the case of other substation apparatus) closes momentarily and energizes the substation general alarm relay 150 over a circuit including the selector contacts 441 and the general alarm bus-bar 70. This relay at once makes its own retaining circuit at contact 154-, which is in series with the contact 157 of the definite time limit relay 156. This relay 156 is simultaneously energized by the closing 01 contact 153. The closing of contact 152 causes a current similar to a circuit-breaker-opening indicating current to be transmitted over the indicating circuit, the connections of the substation battery to the indicating busbars 7 5, 76 being taken through the telephone push contacts 167, 168 and the selector contacts 33, 34, whilst the connection from the busbar 75 to the auxiliary indication relay 130 is taken through the contacts 32, 152. The auxiliary indication relay 130 and the polarized relay 200 at the control station are thus bot-h energized, the latter in a direction to close its contacts 202 and energize the coil 215 The operation of the auxiliary indication relay 130 completes another circuit from the indicating busbar 75 to the control station through the contacts 155, 132, 23, 51, F the pilot wire A the contacts F, 251, 281, 291, 301, 218 (closed by operation of the coil 215) the control station general alarm relay 350 and the contact 240, this circuit being in parallel with the previously traced portion of the indicating circuit including the pilot Wire A and the polarized relay 200. Thus the operation of the substation general alarm relay 150 in the normal zero position causes the energization both of the control station general alarm relay 350 and of the control station polarized relay 200. The former relay energizes the auxiliary general alarm relay355, which retains itself at contact 357 through the stop alarm push contact 337 and the auxiliary reindioation relay contact 365 and also completes at contact 356 the circuit to the buzzer 331 and red lamp 332. The closing of contact 217 energizes the general reindication relay 370, which makes its own retaining circuit at contact 372 through the selector contacts 230 closed in the first four selector positions, and also energizes the auxiliary reindication relay 360 at contact 371. This latter relay makes at contact 361 its own retaining circuit which passes either through the contacts 271, 336 on the selecting and stop alarm pushes or through the selector contacts 232. The closing of contact 362 makes a further energizing circuit for the buzzer 331 and the opening of contact 365 breaks the retaining circuit for the auxiliary general alarm relay 355 (whose main energizing circuit is however still complete.)

The contacts 373, 374 on the general reindication relay bridge the selecting push contacts 273, 274C and consequently the operation of this relay starts an express selecting and indicating cycle, the general alarm relays 350, 355 being deenergized as soon as the cycle starts. The retaining circuit for the general reindication relay 370 is broken after the selectors pass the fourth position, but the control of the express selecting cycle has meanwhile been taken over by the contacts 363, 364 on the auxiliary reindication relay in series with the cam-operated contacts 227, 228. The cycle therefore proceeds to enable the indicating mechanism to give a record of the conditionof the substation apparatus, whereby when the operator responds to the alarm signal he can see at once what change has occurred to cause the alarm. When the cycle is complete and the normal zero position again reached, the cam-operated contacts 227, 228 open and stop the cycle, but the auxiliary reinclication relay still remains energized over the circuit including the stop alarm push contact 336 and the selecting push contact 271, so that the buzzer continues to sound. Depression of either of these pushes will stop the buzzer and the operator can take what steps he thinks fit to deal with the situation, the system now being at rest in its normal condition. It should be mentioned that the substation general alarm relay 150 ms meanwhile been deenergized owing to the breaking of its retaining circuit at contact 157 at the expiration of the time lag of the relay 156.

If now the change of condition occurs when the selectors are at rest in any selected position other than the normal zero position, the operation of the flick switch 16 on any circuit-breaker other than the selected circuit-breaker will energize the general alarm. relay 150. This exception is made in view of the fact that it is not desirable to initiate a general alarm signal when the change of condition results from the transmission of an executive current from the control station, whilst if the change occurs automatically when the circuit-breaker is actually selected, the indicating circuit will be complete and the change will be at once apparent without an alarm signal. The operation of the general alarm relay 150 in this case will cause current to flow over the first pilot wire circuit to the control station general alarm relay 350 (one or other of the contacts 213, 218 and also the contact 131 being closed owing to the indicating currents flowing at the time) but the parallel circuit over the second pilot wire to the polarized relay 200 will not in this case be made owing to the fact thatthe selector contacts 32 are open. The control station general alarm relay 350 will act through its self-retaining auxiliary relay 355 to complete the buzzer circuit, .but will itself be deenergized as soon as the definite time limit tacts 7,

relay 156 breaks the retaining circuit to the substation general alarm relay 150.

A generally similar operation occurs in the event of a general alarm signal being initiated whilst metering is in progress. Provision is made for the initiation of this signal by the automatic operation of the circuit-breaker associated with the selected position as well as by the operation of any other circuit-breaker. For this purpose the selector contacts 43 are provided and the generalalarm relay 150 is then energized through these contacts and the auxiliary general alarm busbar 71, the circuit also including the second meter relay contact 126 (now closed). If the metering source in any position happens to be closely associated with the circuit-- breaker in the same position, an automatic change may be readily apparent from the movements of the meter pointer, and in such cases the selector contacts 43 may be omitted so that a general alarm signal is not transmitted during metering in such a position if due to a change in the condition of the associated circuit-breaker. It will be appreciated that, when metering is in progress, since no indicating currents are flowing the auxiliary indication relay 130 and the control station polarized relay 200 are both de energized and the previously described circu t to the control station general alarm relay 350 through the first pilot wire A? is broken at both ends. This ditliculty is obviated at the substation end by the provision of the contact 125 on the second meter relay 120 and at the control station end by the provision of the contact 302 on the meter switch 300. Thus when the substation general alarm relay 150 is energized during metering, its contact 151 breaks the metering circuit, and its contact 155 completes a connection from the indicating busbar 7 5 through the contacts 125, 23, 51, F the pilot wire A and the con- 251, 302, to the control station general alarm relay 350, the remainder of this circuit being as previously traced. Thus the control station buzzer will sound, and the general alarm relay will be deenergized after the time interval determined by the definite time limitrelay 156.

It should be mentioned that, since the energizing circuit of the relay 156 includes the contacts 11 1, 91 and 82 (so that this relay is not energized whilst the first meter relay or the selector relay or the executive relay is functioning), the time limit for deenergization of the general alarm relay does not commence until such functions have been completed. The time limit of the relay is chosen long enough to allow time for the general alarm apparatus at the control station to operate.

It now remains to describe the efiect of the temporary borrowing of the first and second pilot wires A A5 for protective purposes in the various conditions of the remote control system. As mentioned above, the tripping and stabilizing relays E F e f at the two ends of the protected feeder B are energized independently and consequently may not operate exactly simultaneously. There are therefore three possible cases to be considered. namely the simultaneous disconnection of the two pilot wires A A at both ends, the momentary energization of the pilot wires from the pro tective battery /l at the control station end owing to the operation of the tripping and stabilizing relays e f at that end before the tripping relay F at the substation end, and the momentary energization of the two pilot wires from the protective battery H at the substation end owing to the operation of the tripping and stabilizing relays E F at that end before the trippin relay 7 at the control station end.

It the protective apparatus operates when the remote control system is in its normal zero or eral alarm position, no harm can arise from the temporary disconnection of the first and second pilot wires A and A since no currents are flowing therein. Moreover since the first pilot wire circuit is broken at the control station at contacts 213, 218 when the polarized relay 200 is deenergized, the energization of these pilot wires from the substation protective battery l-I will have no ef feet. At the substation end however, there a complete circuit across the two pilot wires A A including the auxiliary indication relay 130 and the first meter relay 110. Consequently during the very short interval in which the protective battery It at the control station could be connected across these pilot wires, a current would flow in this circuit which would operate the auxiliary indication relay 130 and break the circuit to the first meter relay at contact 131, the auxiliary indication relay perhaps being energized and deenergized a few times. Since however this relay is quicl-1-acting and the first meter relay has a short time-lag, no harmful eflect can be produced on the remote control system.

In. the case when the remote control system is at rest in a selected position other than the general. alarm position with the indicating currents flowing. the only effect of the temporary disconnection of the two pilot wires A and A will be to suspend the flow ct indicating currents until the protective gear has operated and reestablished the re mote control circuits. At the control sta tion while indicating currents are flowing there a complete circuit across the first and second pilot wires A A through the general alarm relav but current cannot flow in this ci cuit from the substation protective battery H, since prior to the connection of the battery to the pilot wires A A these wires must be disconnected. as a result of which the control station polarized relay 200 will be deenergized and will open the first pilot wire circuit at contact 213 or 218 be-- fore current can flow to the general alarm relay 350. At the substation end the conditions will be the same as for the general alarm position.

It now the protective gear borrows the pilot wires A A during the selecting process after the first half-notch movement is completed, i. e. when the release relay 223 is connected across the first and second pilot wires A A the temporary disconnection of these pilot- \\'ires from the remote control system ill delay the completion of the selecting movement but will not have any other harmful effect. As previously mentioned the release relay is polarized so that it remains unall ected by any currents passing through it from the substation protective battery H. At the substation, the condition of the first and second pilot wires is at first the same as in the general alarm or other selector position, but when the substation selector 20 has completed its movement, the substation battery will be connected across the two pilot wires through the contacts 22, Thus it may happen that the substation remote control battery 50 and the control station protective battery A are momentarily connected directly to oppose one another over a circuit including only the two pilot. wires A A but this will have no harmful eilect if the two batteries are suitably chosen.

The performance of an executive function is confined wholly to the third and fourth pilot wires A A and remains unallected by the operation of the protective gear.

In the case when a metering circuit is established, the operation of the protective gear will similarly have no effect for the metering circuit includes only the third and fourth pilot wires A A" and there is no complete circuit at either end across the first and second pilot wires A 93. Thus at the substation the second meter relay holds the first pilot wire circuit open at contacts 123 125 and at the control station the meter switch holds the second pilot wire circuit open at contacts 305, 306.

If it should happen that the protective gear operates during the process of establishing a metering circuit whilst the meter switch 300 is in position. the temporary disconnection of the two pilot wires A A? will break he circuit of the auxiliary meter relay 310 and the first meter relay 110. If this occurs before the expiration of the time-lag of the first meter relay and of the electromagnetic locl; e15, the ellect will be to deenergize the relays 110, 310 and leave the meter switch locked in the 90 position. The normal. process will continue immediately the protective gear restores the pilot wires. If the disconnection of the pilot wires occurs after the expiration of the time-lag, the first meter relay 110 will be temporarily deenergized, but the second meter relay 120'will remain energized. The meter switch 300 will continue to rotate to the 180 position since the lock is held released over the retaining circuit including contacts 304-, 317, and the metering circuit will be established when the pilot wires are restored.

For the case of operation of the protective gear during release metering operations when the meter switch is in the 27 0 position, the only possible interference is from the temporary disconnection of the second pilot wire circuit, since the first pilot wire circuit is at this stage open at both ends. In order to prevent failure to energize the release meter relay 135 owing to protective interference, the time during which the contacts 305, 307 remain closed during rotation of the meter switch is arranged to be greater than the longest time of interference from the protective gear. This ensures that there will be at least a momentary transmission of current either before or after the protective operation, and since the release meter relay 1 85 is a quick-acting relay, such momentary current will in any event be sufiicient to ensure its operation.

' From the cases above described it will also be clear that the temporary borrowing of the first two pilot wires for protective purposes will not have any harmful eifect during other conditions of the remote control system, such for example as when telephone or general alarm currents are flowing.

It will be appreciated that the arrangement above described has been given by way of example only and may be modified in various ways within the scope of the invention. Thus for instance the particular allocation to the individual pilot wires of the various remote control functions above described, may be departed from to some extent provided that any rearrangement does not involve harmful interference with the remote control system when the two pilot wires are borrowed for protective purposes. Again the above arrangement has been described primarily with the use of a protective system arranged according to the prior United States Patent No. 1,765,887 above referred to, but

' it will be appreciated that other forms of protective system requiring the use of two pilot wires may be subtituted therefor, if necessary, with consequent detail alterations in certain parts of the remote control apparatus.

W hat we claim as our invention and dcsire to secure by Letters Patent is 1. A combined remote control and protective system for the selective remote control from a control station of apparatus units at an electric power substation and for the pro tection of a feeder or like circuit lying adjacent to such system, including in combination four pilot wires connecting the two stations and normally forming part of the remote control system two of the pilot wires being capable of being borrowed for protective purposes when required, a D. C. source of E. M. F. associated with the protective system at each end, a transfer device at each end of the protective system, means whereby each transfer device when operated by the protective gear acts to disconnect the two borrowable pilot wires from the remote control system at the adjacent end, means whereby either transfer device may act in accordance with the protective requirements to connect the borrowable pilot wires to the adjacent protective source of M. E, apparatus at the control station for transmitting selecting currents over the two unborrowable pilot wires to the substation, a selector at the substation to which step-by-step movements can be imparted for the successive selection of individual apparatus units, a D. C. source of E. M. E. in the substation associated with the remote control system, means the substation acting in response to a selecting current to cause the selector to perform one stepped movement, means whereby 'on completion of such movement the selector causes the remote control source of E. M. F. to be connected to the two borrowa-ble pilot wires with a polarity opposite to that with which the adjacent protective source of E. M. F. can be connected to such pilot wires, means whereby the control station apparatus for transmitting the selecting currents remains locked against further operation after a selecting current has been transmitted, and a polarized release relay in the control station unresponsive to current received over the borrowable pilot wires from the protective source of E. M. F. but acting when energized by the current transmitted from the remote control source of E. M. F. on completion of the selector movement to unlock the control station apparatus.

2. An electric selective remote control system for a number of circuit-breakers or other apparatus units at an electric power substation, including in combination four pilot wires connecting the substation and the control station of which two are retained exclusively for remote control purposes whilst the other two normally serve for remote control purposes but are available for temporary borrowing for other purposes, means for disconnecting the two borrowable pilot wires from the remote control system when required for such other purposes and for returning them to their normal remote control connections when no longer so required, apparatus at the control station for transmitting selecting currents over the two unborrowable pi ot wires to the substation, a selector device at the substation acting in response to the selecting currents to select individual apparatus units, means whereby when an apparatus unit is selected a current for indicating the condition of the selected unit is transmitted to the control station over one of the borrowable pilot wires and one of the unborrowable pilot wires, an indicator device at the control station responsive to the indicating currents, an alarm apparatus at the substation operative in the event of a change occurring automatically in the condition of the controlled apparatus units, an alarm apparatus at the control station associated with the substation alarm apparatus, and devices operative While the indicating currents are flowing in the one borrowable pilot wire to prepare an alarm circuit including the other borrowable pilot wire over which the substation alarm apparatus can transmit current for the energization of the control station alarm apparatus.

3. An electric selective remote control system for a number of circuit-breakers or other apparatus units at an electric power substation, including in combination four pilot wires connecting the sub-station and the control station, apparatus at the control station for transmitting selecting currents over the third and fourth pilot wires to the sub-station, a selector device at the sub-station acting in response to the selecting currents to select individual apparatus units, means whereby when an apparatus unit is selected a current for indicating the condition of the selected unit is transmitted to the control station over the second and forth pilot Wires, an indicator device at the control station responsive to the indicating currents, an alarm apparatus at the sub-station operative in the event of a change occurring automatically in the condition of the controlled apparatus units, an alarm apparatus at the control station associated with the substation alarm apparatus, an auxiliary relay connected in series with the second pilot wire at the sub-station and acting while the indicating currents are flowing to prepare an operative connection from the sub-station alarm apparatus to the first pilot wire, means associated with the illdicator device at the control station for connecting the control station alarm apparatus to the first pilot wire while the indicating currents are flowing, and means whereby the operation of the sub-station alarm apparatus while the indicating currents are flowing causes the completion of an alarm circuit over the first and fourth pilot wires for the energization of the control station alarm apparatus.

4. The combination with the features set forth in claim 3, of a protective system for a feeder or like circuit lying adjacent to the remote control system, and devices operated by the protective gear whereby the first and sec ond pilot wires are transferred when required from the remote control system to the protective system and are returned to their normal remote control connections as soon as their fer device may act in accordance with the v protective requirements to connect the borrowed pilot wires to the protective source of E. M. F. at the adjacent end, and means whereby the devices operative to prepare the alarm circuit act on the disconnection of the borrowable pilot wires at either end to break the alarm circuit and thereby to prevent inadvertent energization of the control station alarm apparatus from the protective source of E. M. F.

6. An electric selective remote control system for a number of circuit-breakers or other apparatus units at an electric power substation, including in combination four pilot wires connecting the substation and the control station of which two are retained exclusively for remote control purposes whilst the other two normally serve for remote control purposes but are available for temporary borrowing for other purposes, means for disconnecting the two borrowable pilot wires from the remote control system when required for such other purposes and for returning them to their normal remote control connections when no longer so required, apparatus over the control station for transmitting selecting currents over the two unborrowable pilot wires to the substation, a selector device at the substation acting in response to the selecting currents to select individual apparatus units, means whereby when an apparatus unit is selected a current for indicating the condition of the selected unit transmitted to the control station over one of the borrowable pilot wires and one of the unborrowable pilot wires, an indicator device at the control station responsive to the indicating currents, at least one metering source in the substation, at least one meter in the control station which can be connetced to the corresponding substation metering source over a clean circuit including the two unborrowable pilot wires, means at the control station for transmitting an initiating current to the substation over one unborrowable pilot wire and the borrowable pilot wire other than that utilized for the indicating circuit, a

time-lag relay in the substation acting in response to the initiating current to connect the substation metering source to the two unborrowable pilot wires, and a quick-acting relay at the substation which is connected in series with the borrowable pilot wire utilized for carrying the indicating current and acts whenever current is flowing in such pilot wire to disconnect the other borrowable pilot wire from the time-lag relay.

. 7. The combination with the features set forth in claim 6, of means whereby the control station apparatus for transmitting the initiating current to the time-lag relay is held locked in the event of temporary disconnection of the borrowable pilot wires before the completion of the time-lag of the relay, whereby the normal process of energizing such relay recommences immediately the pilot wires are reconnected.

8. The combination with the features set forth in claim 6, of means whereby the control station apparatus for transmitting the initiating current performs the furtheroporation after such current has been transmitted of connecting the meter to the unborrowable pilot wires, an electro-magnetic locking device normally acting to prevent the performance of such further operation, an auxiliary relay at the control station responsive to the initiating current, and means whereby such auxiliary relay acts to release the locking device after a time-lag corresponding to that of the substation time-lag relay.

9. A combined remote control andprotective system for the selective remote control from a control station of apparatus units at an electric power substation and for the protection of a feeder or like circuit lying adjacent to such system, including in combination four pilot wires connecting the two stations and normally forming part of the remote control system, two of the pilot wires being capable of being borrowed for protective purposes when required, a source of E. M. F. associated with the protective system at each end, a transfer device at each end of the protective system, means whereby each transfer device when operated by'the protective gear acts to disconnect the two borrowable pilot wires from the remote control system at the adjacent end, means whereby either transfer device may act in accordance with the protective requirements to connect the borro-wable pilot wires to the adjacent protective source of E. M. E, a time-lag relay connected between the two borrowable pilot wires at the substation and controlling the performance of a remote control function at that station, means at the control station for transmitting a current for the energization of such time-lag relay, and means for preventing inadvertent operation of the timelag relay resulting from the temporary connection thereof to the protective source of E. M. F. comprising a quick-acting relay connected in series between one borrowable pilot wire and the time-lag relay and acting when energized to break the connection between the other borrowable pilot wire and the time-lag relay;

10. The combination with the features set forth in claim 9, of means whereby the control station apparatus for transmitting current for the energization of the timelag relay is held locked in the event of the temporary disconnection of the borrowable pilot wires before the completion of the time-lag of the relay, whereby the normal process of energizing such relay recommences immediately the pilot wires are reconnected.

In testimony whereof we have signed our names to this specification.

BRUCE HAMER LEESON. DOUGLAS EDWARD LAMBERT. 

